The present invention relates to an automotive gauge system which utilizes a power line carrier.
Electrical automotive gauges are well known devices used to monitor various mechanical functions on various types of vehicles and equipment. Conventionally, these instruments have required a large wire bundle to separately supply power, sender, illumination and warning lamp information to each gauge. Typically, instrument installations can contain anywhere from thirty to over one hundred wires in some industrial applications. As a result, wiring the instrument panel can be a time-consuming and intricate process. Furthermore, large numbers of bulky wire bundles are difficult to work with, particularly in applications where space is limited, such as behind the dashboard of a vehicle.
In U.S. Pat. No. 5,539,388, a system is disclosed for transmitting and receiving telemetry and control signals over existing direct current power wiring. However, the modules in this system are all capable of two-way communication, as the system is intended primarily as control system, which adds to the complexity of the system. Furthermore, the signals are coded as a pulsed current signal. In this patent, the difficulty of using high-frequency carriers in an automotive electrical system is acknowledged. The DC power supply in an automotive system has a very low impedance, which causes difficulties when attempting to impress high-frequency carriers on a power line. As well, it is indicated that use of such control signals will interfere with other components of the system.
Therefore, there is a need in the art for an automotive gauge system using a power line carrier where multiple data sources can connect to corresponding gauges using a common transmission network.